The present invention relates to an automatic sheet feeder for a typewriter or like office machine, with a platen roller, comprising a feed device with a friction stripper roller, the device being selectively actuable by the platen roller for feeding individual sheets from a pack of sheets disposed in a magazine to the platen roller of the typewriter, the stripper roller being connected to the platen roller by means of a mechanical transmission.
Various types of sheet feeder of the above-indicated kind have been proposed. In one type the mechanical transmission which makes the connection between the platen roller of the typewriter and the stripper roller comprises a free wheel. The free wheel operates in such a way that, when the platen roller rotates in the opposite direction to the feed movement of a sheet, the stripper roller is positively rotated to feed a sheet towards the platen roller while when the platen roller is rotated in the direction of feed movement of the sheet, the stripper roller is not rotated.
This known feeder suffers from the disadvantage that the stripper roller feeds a sheet whenever the platen roller is rotated in the opposite direction to the feed movement, for example to carry out corrections in previously typed or printed lines, thereby giving rise to blockages in the subsequent feed of further sheets.